And until a couple of years ago, we also allowed it.

    >The Treaty on Open Skies establishes a program of unarmed aerial surveillance flights over the entire territory of its participants. The treaty is designed to enhance mutual understanding and confidence by giving all participants, regardless of size, a direct role in gathering information about military forces and activities of concern to them.
    >[...]
    >On 22 November 2020, United States official sources [...] announced that the six-month period was over and the U.S. was no longer a party to the Treaty.

https://en.wikipedia.org/wiki/Treaty_on_Open_Skies